LOCKHART, Texas (AP)- A hot air balloon carrying 16 people caught on fire and crashed in Central Texas, and authorities say it appears no one survived.

Erik Grosof with the National Transportation Safety Board says a full-bore investigation was to begin Sunday after more federal officials arrive.

Authorities would not confirm the exact number of deaths in Saturday’s crash, but Lynn Lunsford with the Federal Aviation Administration said the balloon was carrying at least 16 people. The Caldwell County Sheriff’s Office said in a statement that it didn’t look like anyone survived.

Robert Sumwalt with the National Transportation Safety Board cautioned Sunday that investigators are still determining how many people were aboard the balloon when it crashed Saturday morning, but that he could confirm at least 16 had died.

That makes it one of the worst hot air balloon crashes in U.S. history.

During the brief news conference in Washington, D.C., Sumwalt said NTSB investigators were just beginning the process of determining what caused the balloon to crash.

He offered few details but said they would be looking into whether the operator of the balloon filed a passenger manifest before taking off, because balloons do not usually file flight plans.

If 16 people were killed, it would be the one of the worst such disasters, possibly the worst in U.S. history.